Parabolic reflector antennae called “satellite dishes” have been used to communicate with orbiting satellites since about the time of the first satellite launch in the late 1950s. Interestingly, the parabolic antenna, a dish-shaped structure as used today, was first built and used in 1888 by Hertz to demonstrate the existence of electromagnetic waves theoretically predicted slightly earlier by Maxwell. More recently, since the 1980s, satellite dishes have been available for use by consumers to receive television broadcast signals. As more satellites are being launched, providing more television and other digital media broadcasts, the use of satellite dishes to receive the broadcast signals increases as well.
However, during cold weather such as during the winter seasons in both latitudes, snow and ice can accumulate on a satellite dish, thereby degrading the signal, and even sometimes completely interrupting the signal. When this happens, the snow or ice needs to be physically removed in order to obtain the “clean” signal again, e.g., by someone going outdoors to remove the accumulation. Devices for de-icing satellite dishes are known, but can vary widely according to the particular type of satellite dish that is being protected from these environmental precipitation problems.
Early home satellite dishes that communicate in the “C-Band” are generally about 2 to 6 feet in diameter and have a solid dish surface, whereas other, more special-purpose dishes can be made of a metal mesh surface. Also, newer, smaller “Ku-band” solid surface satellite dishes are being used, with a diameter of about 18 inches. This invention is directed to these home satellite dishes. This invention is primarily directed to C-band and Ku-band, solid antenna dishes.
U.S. Pat. No. 5,010,350 (Lipkin et al.) shows an anti-icing and de-icing system for reflector-type microwave antennas (i.e., “satellite dishes”), including a plurality of radiant heating elements attached to the rear surface of the antenna (see FIGS. 1-2, items 42 and 43 and column 5, lines 12-32).
U.S. Pat. No. 5,861,855 (Arsenault et al.) shows an arrangement for de-icing a satellite dish antenna including temperature-sensing, signal degrade monitoring and heater control features. More particularly, this document shows control of satellite dish heaters, in general, with smaller Ku band antenna, which are generally 18 inches in diameter, and which are generally more sensitive to signal degradation due to snow, ice or frost accumulation on the dish (for example, see top of column 3) as compared with larger C-band dishes.
U.S. Pat. No. 5,617,107 (Fleming) shows a multi-layer heated microwave antenna that can be retrofit to existing antenna installations, and includes a resistance heater grid and thermostat. In FIG. 7, a generally circular heater structure (170) with a notch is shown. The heater can be attached to the rear surface of the satellite dish using an adhesive, see the last three paragraphs of column 6. However, an additional backing plate 177 is required to be placed onto the heater structure.
U.S. Pat. No. 6,195,055 (Jones) shows a dish antenna heating assembly including a heating element (item 16, front page figure) and a plurality of cover sections (14) adhesively attached onto the heating element.
U.S. Pat. No. 4,866,452 (Barma et al.) shows a heated dish antenna including a self-regulating sheet heater.
U.S. Pat. No. 6,100,851 (Jones) shows a satellite antenna heating system including voltage measuring circuitry.
However, all of these arrangements include multi-element combinations of parts, not all being necessary, or do not provide a generally complete coverage of the rear surface of the satellite dish for nearly-total heat application, and high melting accumulation-removal efficiency. More particularly, none of these documents provide a two-piece conforming heater structure taught herein made up of a single generally circular piece of vinyl chloride (“vinyl”) plastic support sheet with a serpentine-spiral heating cable attached to the support sheet. The diameter of the circular piece of plastic sheet corresponds generally to the diameter of the rear surface of the satellite dish where the heater assembly is attached, e.g., by adhesive.
Therefore, there is a need for an easy-to-attach satellite dish heater with thermostatic control to maximize de-icing and anti-icing capability during cold weather (i.e., less than 32° F.) and precipitation conditions.